The acoustical contribution of the room or surroundings where music is played has much to do with the enjoyment of the sounds. Smaller rooms and those with more sound-absorbing materials tend to have less reverberation than larger rooms and those containing more reflective surfaces. Often the area where music is being recorded or played back does not have the desired acoustical characteristics, for example reverberation. Reverberation simulators have been proposed to meet this problem. Typically they have used a few taps on a delay line: two or three taps, usually not more than four or five. The output of one or more of the taps is fed back to the input to generate the reverberation through the delay line and output from the taps is also used as the reverberated output of the simulator. Due to the feedback loop the pattern of the delay line tap outputs fed back, eventually, after a few cycles of operation, produces a detectable pattern or "flutter echo" which distorts the system performance. As the feedback is increased to lengthen the reverberation decay time, ringing and resonance occur, and finally complete system instability occurs as oscillation builds up. The use of more taps does little to correct this problem: the pattern is still detectable--it is just a more complex pattern, and the problem of instability remains. Another approach uses various multi-loop delay algorithms based on the work of Schroeder, and requires costly high-speed digital signal processing or very critical analog circuit design and analog memory.